Some refrigeration chillers are oil-based lubrication systems that employ oil to lubricate a bearing. In such chillers, a portion of the oil adheres to and is maintained on the bearing surfaces as a film for a relatively long period of time after the chiller and its active oil delivery system is shutdown. As such, when oil is used as a bearing lubricant, at least some of the oil will remain on the bearing surfaces to provide for initial bearing lubrication when the chiller starts up again. Such residual oil can, to at least some extent, be relied upon to lubricate the bearings until the chiller's oil delivery system comes to actively provide oil to the bearing locations. In contrast, an oil free chiller is a type of a refrigeration chiller that, in some cases, may employ a centrifugal compressor, wherein impellers are mounted on a shaft for rotation using rolling element bearings lubricated only by the refrigerant which constitutes the working fluid of the chiller system. Accordingly, the liquid refrigerant is provided (1) to the rolling element bearings (e.g., immediately upon chiller start-up, during chiller operation, and during a coastdown period subsequent to shutdown of the chiller); and (2) to the drive motor of the chiller's compressor for motor cooling purposes. A variable speed-driven motor can be used in the refrigeration chiller to drive the compressor. The oil free chiller does not require or employ an oil-based lubrication system. Accordingly, when refrigerant is used as a bearing lubricant, little or no residual refrigerant remains on the bearing surfaces when the chiller system shuts down (the refrigerant drains away from or boils off of the bearing surfaces leaving an essentially dry bearing). Thus, oil free chillers have unique difficulties and challenges both at chiller start-up and subsequent to chiller shutdown.